Blended ROAS explained
Short answer: blended ROAS is total revenue ÷ total ad spend across every channel. It ignores who-gets-credit attribution and tells you the real return on all the money you put into ads.
Open any ad platform and it will happily report a glowing ROAS — because each one counts conversions it touched, even when several platforms touched the same sale. Add those numbers up and you get a fantasy. Blended ROAS cuts through that by looking at the business as a whole.
How to calculate it
Take all the revenue for a period and divide it by all the ad spend for the same period. If you made $100,000 and spent $25,000 on ads, your blended ROAS is 4.0 (400%) — regardless of what Google and Meta each claimed.
Blended ROAS vs platform ROAS
Platform ROAS is useful for steering one channel, but it double-counts across channels and leans on attribution windows you don't control. Blended ROAS is the reality check: if platform numbers look great but blended ROAS is flat, your channels are mostly claiming credit for the same customers.
Blended ROAS vs MER
The two are nearly the same measurement. MER (marketing efficiency ratio) also compares total revenue to total ad spend; "blended ROAS" is just the more common phrase when you start from a ROAS mindset. Use the ROAS & MER calculator to see both side by side.
Common mistakes
- Summing platform ROAS. That overstates performance every time.
- Judging ROAS without margin. A 4.0 ROAS can still lose money on thin margins — compare to your break-even ROAS.
- Mixing time windows. Revenue and spend must cover the same period.
FAQ
What is blended ROAS?
Total revenue divided by total ad spend across all channels combined.
How is blended ROAS different from MER?
They measure the same thing; MER is the efficiency-ratio framing of the same total-revenue-over-total-spend math.
Why is my platform ROAS higher than blended ROAS?
Platforms each claim the same conversions, so summed platform ROAS overstates results. Blended counts each sale once.